In contrast to functional electrical stimulation (FES) where a muscle or nerve, for performing muscle contraction or for influencing other nerve functions, is stimulated electrically via contacting electrodes so as to support and/or replace particular physiological processes, in the functional magnetic stimulation (FMS) a nerve activation which may, for instance, lead to a muscle contraction, is triggered without contact by appropriate magnetic fields.
The functional magnetic stimulation has the substantial advantage over the functional electrical stimulation with electrodes disposed on the skin surface that pain sensors being within the skin are activated substantially less and the use is felt to be much more comfortable while comparable neuromuscular activation takes place. This is due to the fact that the pain sensors are in high-impedance tissue layers as compared to lower tissue portions. The current flow with electrical stimulation thus causes relatively high electric field strengths especially in the field of pain sensors while the effect-relevant induced eddy currents in the case of magnetic stimulation are substantially stronger in the low-impedance lower tissue than in the high-impedance tissue closer to the surface.
Furthermore, in the case of the functional magnetic stimulation the effort and the risk is, due to the lapse of the implantation of nerve or muscle electrodes which is frequently necessary with the functional electrical stimulation, substantially lower and the acceptance is higher. Contrary to this, however, the targeted stimulation of particular nerves or muscles via the magnetic field is more difficult than with the direct electrical stimulation by means of skin electrodes or implanted electrodes. It is especially very difficult when stimulating lower regions to reach particular points, so-called motor points, with the magnetic field and to achieve, for instance, the contraction of the desired muscles.
Another disadvantage of the functional magnetic stimulation are metal elements within the body region to be stimulated, in which inadmissibly high currents are induced and a dangerous heating of the metal elements and of the surrounding tissue may occur. As examples of such metal elements implants, artificial joints, or the like are mentioned.
An example of a device for magnetic stimulation is described in WO 2009/126117 A1. Here, a magnetic field is induced in lower tissue layers by means of a magnetic coil, which results in a depolarization of neuronal cells leading to muscle contractions of particular muscles in particular body regions.
Another method and a device for neuromagnetic stimulation has become known from EP 0 617 982 A1, wherein a focused ultrasonic beam is superimposed to the magnetic field, with the intention of enabling a more precise spatial stimulation.
A method and a device for pelvic floor training by means of magnetic stimulation has, for instance, become known from DE 10 2012 012 149 A1. In addition to magnetic stimulation, the tissue is supplied with oxygen and/or ozone to further support the training and the build-up of muscles.
US 2013/150653 A1 describes a generic device for magnetic stimulation, wherein a detection unit for detecting metal elements within the treated body region in which the magnetic field is induced is disclosed in the form of own measuring coils.